1. Field of the Invention
The present invention relates to a wafer processing method of dividing a wafer along a plurality of division lines to obtain a plurality of individual devices and mounting an adhesive film for die bonding on the back side of each device, the division lines being formed on the front side of the wafer to thereby define a plurality of separate regions where the respective devices are formed.
2. Description of the Related Art
In a semiconductor device fabrication process, a plurality of crossing division lines are formed on the front side of a substantially disk-shaped semiconductor wafer to thereby define a plurality of separate regions where a plurality of devices such as ICs and LSIs are formed. An adhesive film for die bonding called die attach film (DAF) is mounted on the back side of the semiconductor wafer having the devices on the front side. The adhesive film is formed of polyimide resin, epoxy resin, or acrylic resin, and has a thickness of 5 μm to 150 μm, for example. The semiconductor wafer is cut together with the adhesive film along the division lines to obtain the individual devices (see Japanese Patent Laid-Open No. 2009-28810, for example).
In general, a cutting apparatus is used to divide the semiconductor wafer. The cutting apparatus includes a cutting blade having a cutting edge for cutting the semiconductor wafer together with the adhesive film along the division lines. The cutting edge has a thickness of about 20 μm to 30 μm, for example. In cutting the semiconductor wafer together with the adhesive film along the division lines by using the cutting apparatus, the semiconductor wafer with the adhesive film is attached to a dicing tape supported to an annular frame in the condition where the adhesive film mounted on the back side of the semiconductor wafer is attached to the dicing tape. In such a condition that the semiconductor wafer with the adhesive film is supported through the dicing tape to the annular frame, the semiconductor wafer is held on a chuck table and the cutting blade is rotated to cut the semiconductor wafer together with the adhesive film along the division lines. However, there is a case that the cutting edge of the cutting blade may vibrate due to the elasticity of the adhesive film. The vibrations of the cutting edge of the cutting blade may cause chipping of the side surface of each device divided from the semiconductor wafer, so that each device may be degraded in die strength and quality.
To cope with this problem, the cutting blade is positioned so that the outer circumference of the cutting edge slightly cuts into a base sheet of the dicing tape. Accordingly, the cutting edge is supported by the base sheet of the dicing tape in cutting the semiconductor wafer with the adhesive film.